This viewpoint highlights serious differences between ED and other probabilistic reconstructions (see e.g., [1]}[2]}[3]}). To start, it is not clear that these approaches take probability seriously enough: if probabilities are being updated, then this should be accomplished within the framework of probability theory and entropic inference. It is not obvious, for instance, that the operational language of `amplitudes', `experiments', `transformations', etc., is entirely adherent to these more fundamental principles. Another key distinction arises in how probabilities are utilized. Let us explain. An important task in any probabilistic theory is identifying the propositions, or microstates, that are the subject of inquiry.Are we uncertain, for instance, of the rise or fall of a stock index price, which side of a coin has landed face up, or perhaps, the location of a particle? Some approaches, such as quantum Bayesianism [4]} (or `QBism'), for example, assign probabilities to the outcomes of measurements. And certainly, there is nothing strictly speaking `wrong' about this; probabilities are, by design, flexible in this regard. Nevertheless, in doing so, QBists and others (see e.g., [3]}) are aligning themselves to many of the philosophical and (indefinite) ontological commitments of complementarity, and of the Copenhagen interpretation, more generally. How much “physical" insight, after all, can possibly be gained from such a viewpoint?
